Lubricating oil composition



Patented Apr. 26, 1949 2,468,501 wamca'rmo on. comos'mon Eugene Lieber, Chicago, 111., and Aloysius F. Cashman', Staten Island, N. Y., assignors to Standard 01] Development poration of Delaware No Drawing. Application May 22, 1946, Serial No. 671,662

This invention relates to the preparation of a novel oil composition which flows at lower temperatures than the base stock from which it is prepared. More particularly, the invention relates to the preparation of a lubricating oil composition containing two diflerent additives which cooperate to give the lubricant an unexpectedly low stable pour point.

It has been known for some time that pour depressors for waxy mineral lubricating oils can be made by a Friedel-Crafts condensation of long chain aliphatic compounds such as chlorinated paraflin wax with aromatic compounds such as naphthalene. Small amounts, e. g. 0.1% to 2.0%, of such pour depressors may lower the A. S. T. M. pour point of a waxy mineral lubricating oil, for example, from +30 F. down to a temperature ranging from F. to as low as 35 F. or lower, depending upon the particular type of oil used, the nature and method of preparation of the pour depressor, and the concentration in which the lat ter is used. Although it has been found that such a pour depressor may reduce the A. S. T. M. pour point to -30 F. or more, the blend may still have a 40 or 50 higher stable pour point, of the order of or F., as determined by the Test "12" pour stability test, described in Oil and Gas Journal, vol. 42, No. '7, pp. 103-106 (June 24, 1943) In this test the samples of oil are subjected to a series of temperature cycles rangin from F. to higher levels to simulate the rise and fall of temperature during a winter season. This means that when a blend of waxy lubricating oil containin a small amount of pour depressor is stored in the winter in a place where it is subject to the fluctuation of the normal atmospheric temperature, the repeated cycles of alternate warming and cooling will permit the oil blend to become solid at temperatures of 20 or or even 50 5. higher than the A. S. T. M. pour point of such blends.

Another type of pour depressor which is known to the art is a polymeric material obtained by the pyrolysis of fatty acid halides and the like at a temperature of 400 to 750 F. Such materials and their effect in lowering the pour point of waxy lubricating oils are described in E. Liebers U. S. Patent 2,251,550, issued August 5, 1941. Products of this type have been found to lower the pour point to as low as --30 F. However, as in the case of the alkyl-aromatic condensation products described above, these pyroliz ed acyl halides exhibit instability in pour point under fluctuations of temperature, as determined by applying Test V, as described above.

It has now been found, in accordance with the present invention, that if small amounts of both an alkyl-aromatic condensation product and the above-described pyrolized acyl halide are added to a waxy lubricatin oil, surprisingly stable pour 3 Claims. (Cl. 252-52) Company, a corpoints are produced, and intact by carefully adjusting the relative proportions of these two additives the pour point can be so stabilized that solidification of the oil will not result at temperatures as low as --20 F., even though a similar oil containing only one of these additives would solidify at temperatures as high as +4 to +14 F. after being subjected to two or more cycles of. rising and falling temperature.

The alkyl-aromatic condensation product which is used as one of the additives in accordance with the present invention may be more strictly defined as a high molecular weight condensation product of a long. chain aliphatic compound with an aromatic compound selected from the class consisting of aromatic hydrocarbons and hydroxy and amino derivatives thereof.

The polymeric acyl halide derivative. as employed in the present invention, may be defined as a polymeric compound prepared by pyrolyzing,

at about 400 to about 750 F., a compound of the formula RCOX, where R is an alkyl or aromatic-alkyl radical having at least 10 carbon atoms in an aliphatic chain, and X is a halogen. Examples of compounds suitable for forming such a polymeric product are stearyl chloride, phenylstearyl chloride, behenyl chloride, palmityl chloride, and the like.

The alkyl-aromatic type pour depressor may be prepared by any of the large number of methods known to the art, one of the earliest of which was disclosed in U. S. Patent 1,815,022. In making such alkyl-aromatic condensation product, the aromatic compound to be used may be either an aromatic hydrocarbon such as naphthalene, diphenyl, benzene, toluene, amyl-benzene, anthracene, etc., or various hydroxy and amino derivatives of aromatic hydrocarbons, such as phenol, naphthol, cresol, aniline, xylidine, etc. The long chain aliphatic compound is preferably a material such as parafiin wax which is chlorinated to a chlorine content of about 10% to about 20%. Alternatively, such chlorinated wax or equivalent material may be dehydrochlorinated to produce correspondin olefins and the olefins may be condensed with the aromatic compound. Other long chain aliphatic compounds may be used, preferably having more than 10 aliphatic carbon atoms, such as stearic acid, stearyl chloride, octadecyl alcohol, cetyl alcohol, etc. These condensation products are preferably made by the use of a Friedel-Crafts type catalyst such as aluminum chloride, zinc chloride, anhydrous hydrogen fluoride, etc., preferably in the presence 01 an inert solvent such as 1 to 5 volumes of a highly refined kerosene or heavy naphtha or tetrachlorethane, per volume of mixed reactant, followed by hydrolysis and removal of the catalyst and distillation of the reaction product under reduced pressure at a temperature up to about 500 or second additive in accordance with the present invention may be prepared by pyrolyzing an acyl halide or similar compound containing at least carbon atoms in an alkyl group attached to the acyl or COX group, where X is a. halogen. Such acyl halides may be prepared from fatty acids and the like by known processes, for example, by reacting the acid with phosphorus trichloride. Suitable acids are the naturally occurring fatty acids, such as stearlc, palmitic, behenic and the like, or the mixtures of wax acids obtained by the oxidation of parafiin wax. The acyl halide, preferably an acyl chloride, is pyrolized by gently heating at a temperature of about 400 to 750 F. until the evolution of hydrogen chloride has substantially ceased, after which the product is preferably diluted with a suitable solvent and washed free from acid, following which the solvent is removed by distillation at a pressure of 1 to 50 mm. to a temperature of about 500 F. The distillation residue, which is the desired product, is a viscous, gummy material freely soluble in mineral oils. Further details of the preparation of these products may be found in the aforementioned U. S. Patent 2,251,550.

The oil base stocks into which the two pri- 'mary additives described above are incorporated are preferably waxy mineral lubricating oils such as a paraflinic lubricating oil base stock or a mixed base, which may have been subjected to any one or more of the commonly used refining .steps, such as distillation, solvent extraction, acid treating, clay treating, etc., as well as partial dewaxing. Such oil base stock may either be one which is within the known lubricating oil viscosity range, or it may be an oil of much lower viscosity, such as one which is used in the preparation of hydraulic oils, etc., and which may have a viscosity as low as 40 seconds Saybolt at 100 F.

In carrying out the invention, it has been found desirable to use the aliphatic-aromatic type additive in proportion of about 0.1 to 2.0%, based on the lubricating oil base stock, and about 0.01 to about 1.5% of the acyl halide polymer, and it is also desirable to adjust the relative proportions of the two additives so that from 1 to 60 parts of the aliphatic-aromatic additive, more preferably 2 to 20 parts of the same, are used for one part of the polymeric acyl halide material.

' The desirable results obtained by the use of the two additives described in the present specification may be illustrated by the following examples, which, however, are not to be considered as limiting the scope of the invention in any,

way.

EXAMPLE 1 This example illustrates the preparation of a product by the pyrolysis of stearyl chloride and the determination of the A. S. T. M. pour point of blends of various proportions of this product alone in a lubricating oil.

For the preparation of the polymer, 1135 g. of stearyl chloride (prepared by treating stearic acid with P013 in the conventional manner) was placed in a 2-liter flask and pyrolysed in a sand or WoodYs metal bath for 3 hours at 580 F. After the pyrolysis step the product was recovered as a bottoms residue by distilling off volatile and unpolymerizable' materials to 600 1". under a vacuum of about 10-20 mm. mercury pressure. A yield of 923 g. of a dark oil was obtained. This product was found to have good pour depressing properties, as shown by the following data showing A. S, T. M. pour point determinations on a base lubricating oil consisting of a solvent extracted Mid-Continent oil fraction having a Saybolt viscosity at 100 F. of 148 and a viscosity at 210 F. of 42.7 and on blends of this oil with the polymer.

In this example the "pour stability properties of a lubricating oil containing the abovedescribed polymer and an aliphatic-aromatic pour depressor were tested according to the above-described Test V procedure. The aliphatic-aromatic pour depressor was made by condensing about 100 parts by weight of chlorinated paraflin wax having a chlorine content of about 14% with about 15 parts by weight of naphthalene, in the presence of about 40 volumes of refined kerosene solvent per volume of mixed reactant, and in the presence of about 2% parts by weight of aluminum chloride as catalyst, followed by th hydrolysis removal of the catalyst and distillation of the reaction mixture by fire and steam up to about 600 F. The distillation residue was blended to a standardized potency and used as a pour depressor concentrate. The base oil employed in the test was a solvent extracted Mid-Continent lubricating oil fraction containing 3 /2% of a Pennsylvania bright stock and having a Saybolt viscosity at 100 F. of 148 I and a. viscosity at 210 F. of 42.7, and an A. S. T. M. pour point of +25'F.

In the data shown in Table 2 results are given of the tests of oils containing the aliphatic-aromatic pour depressor alone, the stearyl chloride polymer alone, and combinations of the two additives in various proportions. The A. S. T. M. pour point of the various blends are shown, and finally the solid point according to Test V," as measured in cycle 2 of the test, which represents a temperature drop from +30 F. to 20 F. and which has been found by experience to most consistently represent actual field tests of such oils; By the solid point is meant the tem:

perature at which the oil becomes solid during the course of the gradual fall in temperature.

l signifies: "Did not become solid."

It will be noted from the above data that the blended oils containing the two additives exhibited excellent pour stability properties. At concentrations of stearyl polymer from 0.2% to 0.75% the 011 did not become solid during any part of the temperature cycle down to about 20 F., which was the low point oi. the cycle.

EXAMPLE 3 In this example will be described a series of field tests conducted in a winter season at Regina, Canada, and at Bayonne, New Jersey. In these tests a base lubricating oil stock was employed which was the same as that employed in the Test V determinations of Example 2. The aliphatic-aromatic pour depressor used in the tests was employed in one series of tests in the form in which it was originally prepared, which was according to the method described in Example 2; while in another series of tests this additive was modified in the course of its preparation by the addition of 2% to 6% by weight of the reaction mixture of benzal chloride near the close of the period of reaction. This product will be referred to in the tables simply as modified. In each series of tests the amount of aliphaticaromatic additive was 1%, while the amounts of stearyl polymer ranged from to 0.75%. The total number of readings in each series of tests at Regina was approximately 112, and the number at Bayonne was 84. The overall range of temperature at Regina was from about +40 to about 30 F., and the range at Bayonne was from about +50 down to F.

The pour stability rating is the percentage of the time the blends are observed to be fluid for the total period of observation. Data are given for the entire range in temperature and for certain specific ranges which were found to be of interest. The data for times solid indicate the number of observations at which the given sample was found to be solid. The data of these tests follow in Tables 3 and 4.

TABLE 3 Pour Stability Tim Hi h t Raflng es g es Adam"! Solid Solid Pt.

10 to Overall o FII 1'7 Aliphatic-aromatic 34 +12 56 0 gunmodifle l 0 Aliphatlc'aromatic +7 68 14 +225% stearyl polym 1% Aliphatic-aromatic 0 below 25 100 '100 +gi 50% stearyl polym 1% Aliphatic-aromatic 0 below --25 100 100 xiii 75% stearyl poly- 17 Aliphatic-aromatic 24 +9 60 zmodliied 1% Alipbat o-aromatic 18 +1 77 0 +29% steary p ym 1% Aliphatic-aromatic 0 below --25 100 100 325% stearyl polye 1% Aliphatic-aromatic 0 below 25 100 1(1) +0.75% stearyl poly- Tun: 4

Winter field tests at Bayonne, New Jersey [Total oi 8 1 observations for each sample] It will be noted that even small proportions of stearyl polymer in the blend produced a marked eflect in improving the pour stability, properties. By increasing the concentration of the polymer blends still better pour stability ratings were obtained.

It is not intended that this invention be hunted to the specific examples which have been given merely for the sake of illustration, but only by the appended claims in which it is intended to claim all novelty inherent in the invention and all modifications coming within the scope and spirit of the invention.

We claim:

1. A lubricating composition comprising a major proportion of a waxy mineral lubricating 011, about 0.1% to about 2.0% of a high molecular weight condensation product of chlorinated parafiin wax and naphthalene, and about 0.01% to about 1.5% of a polymeric compound prepared by pyrolyzing a high molecular weight fatty acid chloride at about 400 to about 750 F.

( 2. A lubricating composition comprising a large proportion of a waxy mineral lubricating oil, about 0.1% to about 2.0% of a high molecular weight condensation product of a chlorinated parafiin wax with a, naphthalene and about 0.01% to about 1.5% of a polymeric compound obtained by pyrolyzing stearyl chloride at about 400 to about 750 F.

3. A lubricating composition comprising a major proportion of a waxy mineral lubricating oil, about 1% to about 1.25% of a high molecular weight condensation product of chlorinated paramn wax and naphthalene, and about 0.5% to about 0.75% of a polymeric product obtained by pyrolyzing stearyl chloride at about 400 to The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,052,003 Rein Aug. 25, 1936 2,251,550 Lieber Aug. 5, 1941 Mikeska June 30, 1942 

